1. Field of the Invention
This invention relates to a film gate unit for motion picture apparatuses, and more particularly to a film gate unit integrally formed of synthetic resin by molding.
2. Description of the Prior Art
In cinecameras, motion picture projectors or the like, it is well-known that intermittent feeding of unexposed or exposed film supported on a certain surface should desirably be accomplished by slide-contacting such film onto a film gate having a surface of excellent surface precision and very low friction coefficient.
For this purpose, the conventional film gate required a particularly high machining accuracy and the assembly of such a film gate to a motion picture apparatus has involved minute care to ensure that the gate will be positioned within the film aperture in the focal plane of the lens and to warrant the high precision with which the film gate is oriented along the optical axis. Especially, a film gate for use with cinecameras has required the surface thereof to be subjected to a light-intercepting treatment and further coated with a black pigment. Thus, the formation and assembly of the conventional film gate has been very complicated and costly.
Most film gates of the prior art have been manufactured by die-casting a material into a predetermined shape, thereafter machining the thus shaped material and subjecting it to a finishing process, and black-plating it. Then, these film gates have been secured to mounting base plates by means of screws. To enhance the accuracy with which the film gates are secured to the base plates, positioning pins which also serve as guide pins for film have been studded in the base plates so that such pins may be used as the reference to mount the film gates to the base plates. Thus, the mounting of the film gates has required the provision of guide pins studded in the base plates and this has added much to the cumbersome procedures and accordingly aggravated the inefficiency of the machining and assembly. Such film gates have been unsuitable for assembling quantities of them, and necessarily incurred higher expenses.